INVESTMENT SECURITIES - Continuous Unrealized Loss on Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
AFS
AFS, Less than 12 months, Gross unrealized losses	$ (75,797)	$ (2,503)
AFS, Less than 12 months, Fair value	987,402	181,901
AFS, Twelve months or more, Gross unrealized losses	(8,657)	(822)
AFS, Twelve months or more, Fair value	39,089	15,712
AFS, Total, Gross unrealized losses	(84,454)	(3,325)
AFS, Total, Fair value	1,026,491	197,613
Residential mortgage-backed securities
AFS
AFS, Less than 12 months, Gross unrealized losses	(2,106)	(38)
AFS, Less than 12 months, Fair value	60,558	5,324
AFS, Twelve months or more, Gross unrealized losses	(558)	(300)
AFS, Twelve months or more, Fair value	2,089	2,406
AFS, Total, Gross unrealized losses	(2,664)	(338)
AFS, Total, Fair value	62,647	7,730
Commercial mortgage-backed securities
AFS
AFS, Less than 12 months, Gross unrealized losses	(6,503)	(235)
AFS, Less than 12 months, Fair value	63,553	18,127
AFS, Twelve months or more, Gross unrealized losses	0	0
AFS, Twelve months or more, Fair value	0	0
AFS, Total, Gross unrealized losses	(6,503)	(235)
AFS, Total, Fair value	63,553	18,127
Residential collateralized mortgage obligations
AFS
AFS, Less than 12 months, Gross unrealized losses	(14,699)	(1,007)
AFS, Less than 12 months, Fair value	263,668	53,068
AFS, Twelve months or more, Gross unrealized losses	(3,878)	(314)
AFS, Twelve months or more, Fair value	19,095	7,116
AFS, Total, Gross unrealized losses	(18,577)	(1,321)
AFS, Total, Fair value	282,763	60,184
Commercial collateralized mortgage obligations
AFS
AFS, Less than 12 months, Gross unrealized losses	(4,410)	(135)
AFS, Less than 12 months, Fair value	98,776	14,806
AFS, Twelve months or more, Gross unrealized losses	(855)	(198)
AFS, Twelve months or more, Fair value	7,267	5,132
AFS, Total, Gross unrealized losses	(5,265)	(333)
AFS, Total, Fair value	106,043	19,938
Municipal bonds
AFS
AFS, Less than 12 months, Gross unrealized losses	(44,369)	(914)
AFS, Less than 12 months, Fair value	449,658	64,237
AFS, Twelve months or more, Gross unrealized losses	(3,366)	(10)
AFS, Twelve months or more, Fair value	10,638	1,058
AFS, Total, Gross unrealized losses	(47,735)	(924)
AFS, Total, Fair value	460,296	65,295
HTM
HFM, Less than 12 months, Gross unrealized losses	(32)
HFM, Less than 12 months, Fair value	2,443
HFM, 12 months or more, Gross unrealized losses	0
HFM, 12 months or more, Fair value	0
HFM, Total, Gross unrealized losses	(32)
HTM, Total, Fair value	2,443
Corporate debt securities
AFS
AFS, Less than 12 months, Gross unrealized losses	(1,462)	(1)
AFS, Less than 12 months, Fair value	30,259	3,164
AFS, Twelve months or more, Gross unrealized losses	0	0
AFS, Twelve months or more, Fair value	0	0
AFS, Total, Gross unrealized losses	(1,462)	(1)
AFS, Total, Fair value	30,259	3,164
U.S. Treasury securities
AFS
AFS, Less than 12 months, Gross unrealized losses	(2,248)	(173)
AFS, Less than 12 months, Fair value	20,930	23,175
AFS, Twelve months or more, Gross unrealized losses	0	0
AFS, Twelve months or more, Fair value	0	0
AFS, Total, Gross unrealized losses	(2,248)	(173)
AFS, Total, Fair value	$ 20,930	$ 23,175

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer.

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